Primer Cup for a Primer Having Deposited Ignitable Material

ABSTRACT

A cup for a primer facilitates the use of deposited ignitable material, for example, a layered thermite material, within a cup that fits within a standard primer pocket within a firearm cartridge casing or other location designed for a presently available primer. The primer cup includes a tube and a disk. The ignitable material can be deposited on one surface of the disk. The disk can then be inserted within the tube, wherein it is retained within the tube by an inwardly projecting ledge at one end of the tube.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional patentapplication Ser. No. 62/579,141, filed Oct. 30, 2017, and entitled“Primer Cup for a Thermite Primer.”

TECHNICAL FIELD

The present invention relates to primers for firearms and othermunitions. More specifically, a cup is provided for containing theignitable material of a primer, and for holding the ignitable materialwithin a firearm cartridge or within another munition.

BACKGROUND INFORMATION

Cartridges for firearms, as well as other munitions such as largerprojectile cartridges and explosives are often ignited by a primer.Presently available primers and detonators are made from a copper orbrass alloy cup with a brass anvil and containing lead azide or leadstyphnate. When the base of the cup is struck by a firing pin, thepriming compound is crushed between the cup's base and the anvil,igniting the primer charge. The burning primer then ignites anotherflammable substance such as smokeless powder, explosive substances, etc.Lead azide and lead styphnate are hazardous due to their toxicity aswell as their highly explosive nature. Additionally, presentmanufacturing methods are very labor-intensive, with the necessarymanual processes raising costs, causing greater difficulty inmaintaining quality control.

Energetic materials such as thermite are presently used when highlyexothermic reactions are needed. Uses include cutting, welding,purification of metal ores, and enhancing the effects of highexplosives. A thermite reaction occurs between a metal oxide and areducing metal. Examples of metal oxides include La₂O₃, AgO, ThO₂, SrO,ZrO₂, UO₂, BaO, CeO₂, B₂O₃, SiO₂, V₂O₅, Ta₂O₅, NiO, Ni₂O₃, Cr₂O₃, MoO₃,P₂O₅, SnO₂, WO₂, WO₃, Fe₃O₄, COO, Co₃O₄, Sb₂O₃, PbO, Fe₂O₃, Bi₂O₃, MnO₂,Cu₂O, and CuO. Example reducing metals include Al, Zr, Th, Ca, Mg, U, B,Ce, Be, Ti, Ta, Hf, and La. The reducing metal may also be in the formof an alloy or intermetallic compound of the above-listed metals.

A properly designed energetic material, for example, that which isdisclosed in US 2016/0102030, which was invented by K. R. Coffey et al.and published on Apr. 14, 2016, would provide an effective alternativeto presently used primer materials, as well as being safer tomanufacture. The entire disclosure of US 2016/0102030 is expresslyincorporated herein by reference. In addition to the structures andmethods disclosed therein, a primer cup is disclosed herein for easilyinstalling such a primer within a conventional cartridge casing, orwithin another location that is designed to receive a conventionalprimer.

SUMMARY

The above-described needs are met by a primer. The primer comprises atube having a side wall. The tube defines a first open end, a secondopen end, a tube interior, and a central axis. The second open enddefines a ledge projecting towards the central axis. The primer furthercomprises a disk having a first surface, a second surface, and an edge.The disk is dimensioned and configured to fit within the interior of thetube with the periphery of the disk abutting the wall. The disk has anignitable material deposited upon the first surface. The ledge of thetube is dimensioned and configured to resist passage of the disktherethrough.

The above-described needs are met by a cup for a primer. The cupcomprises a tube having a side wall. The tube defines a first open end,a second open end, a tube interior, and a central axis. The second openend defines a ledge projecting towards the central axis. The primerfurther comprises a disk having a first surface, a second surface, andan edge. The disk is dimensioned and configured to fit within theinterior of the tube with the periphery of the disk abutting the wall.The ledge of the tube is dimensioned and configured to resist passage ofthe disk therethrough.

These and other aspects of the invention will become more apparentthrough the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a primer.

FIG. 2 is a side elevational view of a tube for a primer cup.

FIG. 3 is a cross-sectional view of the tube for a primer cup of FIG. 2,taken along the lines A-A in FIG. 1.

FIG. 4 is a top plan view of a tube for a primer cup of FIG. 2.

FIG. 5 is a perspective view of a tube for a primer cup of FIG. 2.

FIG. 6 is a top plan view of a disk for a primer cup.

FIG. 7 is a cross-sectional view of the disk for a primer cup of FIG. 6,taken along the lines B-B in FIG. 5.

FIG. 8 is a side elevational view of a disk for a primer cup of FIG. 6.

FIG. 9 is a perspective view of a disk for a primer cup of FIG. 6.

FIG. 10 is a side elevational view of a primer cup utilizing a tube ofFIG. 2 and a disk of FIG. 5.

FIG. 11 is a cross-sectional view of the primer cup of FIG. 10, takenalong the lines C-C in FIG. 9.

FIG. 12 is a top plan view of a primer cup of FIG. 10.

FIG. 13 is a perspective view of a primer cup of FIG. 10.

Like reference characters denote like elements throughout the drawings.

DETAILED DESCRIPTION

Referring to the drawings, an example of a primer cup is shown. Theillustrated example of a primer cup may be used with a firearmcartridge, or with another munition that utilizes a primer in anycapacity. Although the illustrated example of a primer cup is intendedfor use with an ignitable material that can be deposited on the disk asdescribed below, for example, a thermite priming material, it is notlimited to such use. As used herein, the terms top, bottom, front, back,side, etc. are used for convenience only, and are not intended to limitthe scope of the invention. It is recognized that rotation of thecomponents described herein would result in a different portion of eachcomponent being a top, side, etc.

The primer cup 10 (FIGS. 1 and 10-13) includes a tube 12 (FIGS. 2-5) anda disk 14 (FIGS. 6-9). The tube 12 and disk 14 are formed from amalleable metal, for example, brass, soft steel, or other malleablemetals. The illustrated example is made from brass. The illustratedexample of the tube 12 is generally cylindrical, and the illustratedexample of the disk 14 is generally circular. As used herein, generallycylindrical is defined as sufficiently cylindrical to fit within apresently used primer pocket. Other shapes may be used to conform toother primer pockets without departing from the invention.

Referring to FIGS. 2-5, the tube 12 includes a side wall 15 having afirst edge 16 and a second edge 18. The first edge 16 is substantiallystraight, so that it may conform to the shape of a typical primerpocket. The second edge 18 includes an inwardly projecting ledge 20extending about the interior circumference of the side wall 15. A firstopening 22 is defined at the first edge 16 of the tube 12, and extendsbetween the sidewalls 15. A second opening 24 is disposed within theledge 20. In the illustrated example, the openings 22, 24 are generallycentrally located with respect to the sidewall 15. The side wall 15further includes at least one inward projection 26 disposed a shortdistance inward from the ledge 20. The illustrated example of a tube 14includes four inward projections 26, which in the illustrated exampleare formed as a result of a crimp 28 corresponding to each of the inwardprojections 26.

Referring to FIGS. 6-9, the disk 14 includes a first face 30, a secondface 32, and a peripheral edge 34. The peripheral edge 34 includes afirst portion 36 adjacent to the face 30, and a second portion 38adjacent to the face 32. The edge portion 36 has a larger diameter thanthe edge portion 38, resulting in a circumferential lip 39 being definedby the difference in diameter between the edge portion 36 and edgeportion 38. In the illustrated example, the edge portion 36 has anexterior diameter that corresponds to the internal diameter of thesidewall 15 of the tube 12. The edge portion 38 has an exterior diameterthat substantially corresponds to the internal diameter of the opening24. The thickness of the edge portion 36 corresponds to the distancebetween the ledge 20 and projections 26. The thickness of the edgeportion 38 corresponds to the thickness of the ledge 20. As used herein,the substantially corresponding dimensions are sufficiently close sothat the disk 14 can be retained within the tube 12 as described below.The first face 30 of the disk 14 also includes a recessed portion 40. Inthe illustrated example, the recessed portion 40 has a diameter that issmaller than the diameter of the second edge portion 38, and isgenerally centrally located within the first face 36. In the illustratedexample, the difference between the diameter of the recess 40 and thediameter of the second edge 38 does not substantially exceed twice thethickness of the disk 14. The recessed portion 40 also has a depth thatdoes not substantially exceed half of the thickness of the disk 14. Therecess 14 contains an ignitable material that has been depositedthereon, and one examples of the recess 14 is filled with thermite (FIG.1 shows thermite 42 or other ignitable material 42 in the recess 40). Anexample of a suitable thermite may be prepared according to U.S. patentapplication Ser. No. 14/850,902, which was filed by Kevin R. Coffey etal. on Sep. 10, 2015, and published as US 2016/0102030 on Apr. 14, 2016,the entire disclosure of which is expressly incorporated herein byreference.

An example of a process for making the tube 12 begins with malleablemetal tubing such as brass tubing having an external diametercorresponding to a typical external diameter for a standard primer. Thetube is cut to a length corresponding to or slightly longer than thelength of a standard primer. One end of the tube is bent to form theledge 20. The sidewall 15 of the tube 12 is then crimped to form theinward projections 26.

The disk 14 is made from a sheet of malleable metal, such as a brasssheet. Some examples of the process will form multiple disks 14simultaneously. A press is utilized to form the disk 14 into the shapethat is described above and illustrated in the drawings. Individualdiscs 14 can be cut from the sheet before or after the pressing process.The thermite may be deposited within the recess 40 either before orafter the discs 14 are cut from the brass sheet, depending upon when thepressing process takes place.

Once the disks 14 and tubes 12 are formed, a disk 14 is inserted intothe opening 22 of a tube 12, and moved downward within the tube 12 untilthe second edge portion 38 is within the opening 24, and the first edgeportion 36 abuts the ledge 20, and is retained by the inward projections26. Once the disks 14 are installed within the corresponding tubes 12,an adhesive may be utilized to further secure each disk 14 within itstube 12. Suitable adhesives are known in the art of manufacturingammunition for firearms. As one example, an anaerobic, UV curableadhesive is known to be drawn into the interface between a conventionalprimer and casing, and could also be utilized to adhere the disk within14 to the tube 12. The inward projections 26 may be formed either beforeor after the disk 14 is positioned inside the tube 12.

The present invention therefore provides a primer that includes anignitable material deposited thereon. The ignitable material can in someexamples be a layered thermite material. The primer can be easily andsafely manufactured by depositing the ignitable material on a disk, andthen inserting the disk into a tube to form the primer cup. The primercan be dimensioned and configured to fit within a primer pocket of astandard firearm cartridge or the primer pocket of another munition thatutilizes standard primers.

A variety of modifications to the above-described embodiments will beapparent to those skilled in the art from this disclosure. Thus, theinvention may be embodied in other specific forms without departing fromthe spirit or essential attributes thereof. The particular embodimentsdisclosed are meant to be illustrative only and not limiting as to thescope of the invention. The appended claims, rather than to theforegoing specification, should be referenced to indicate the scope ofthe invention.

What is claimed is:
 1. A primer, comprising: a tube having a side wall,the tube defining a first open end, a second open end, a tube interior,and a central axis, the second open end defining a ledge projectingtowards the central axis; a disk having a first surface, a secondsurface, and an edge, the disk being dimensioned and configured to fitwithin the interior of the tube with the periphery of the disk abuttingthe wall, the disk having an ignitable material deposited upon the firstsurface; and the ledge being dimensioned and configured to resistpassage of the disk therethrough.
 2. The primer according to claim 1,wherein: the tube is generally cylindrical, the tube defining aninternal diameter; and the disk is generally circular, the disk having adiameter that substantially matches the internal diameter of the tube.3. The primer according to claim 2, wherein the ledge extends aroundsubstantially the entire wall, the ledge defining the second open end.4. The primer according to claim 3, wherein the edge of the diskincludes a first edge portion adjacent to the first surface, and asecond edge portion adjacent to the second surface, the second edgeportion having a diameter corresponding to a diameter of the second openend, the disk defining a lip extending between the first edge portionand the second edge portion, the first edge portion defining a firstthickness, the second edge portion defining a second thickness, thethickness of the second edge portion being substantially equal to athickness of the ledge of the tube, the lip of the disk having a widththat is substantially equal to the width of the ledge of the tube. 5.The primer according to claim 4, wherein the wall defines a plurality ofinwardly extending projections, each of the inwardly extendingprojections being disposed a distance above the ledge that issubstantially equal to the thickness of the first edge portion, wherebythe disk is retained between the ledge and the inwardly extendingprojections.
 6. The primer according to claim 1, wherein the walldefines a plurality of inwardly extending projections, each of theinwardly extending projections being disposed a distance above the ledgethat is substantially equal to a thickness of a portion of the edge ofthe disk abutting the wall, whereby the disk is retained between theledge and the inwardly extending projections.
 7. The primer according toclaim 1, wherein the ledge extends around substantially the entire wall,the ledge defining the second open end.
 8. The primer according to claim7, wherein the edge of the disk includes a first edge portion adjacentto the first surface, and a second edge portion adjacent to the secondsurface, the second edge portion being dimensioned and configured tosubstantially fill the second open end, the disk defining a lipextending between the first edge portion and the second edge portion,the first edge portion defining a first thickness, the second edgeportion defining a second thickness, the thickness of the second edgeportion being substantially equal to a thickness of the ledge of thetube, the lip of the disk having a width that is substantially equal tothe width of the ledge of the tube.
 9. The primer according to claim 8,wherein the wall defines a plurality of inwardly extending projections,each of the inwardly extending projections being disposed a distanceabove the ledge that is substantially equal to the thickness of thefirst edge portion, whereby the disk is retained between the ledge andthe inwardly extending projections.
 10. The primer according to claim 1,wherein: the first surface includes a recess defined therein; and theignitable material is deposited within the recess.
 11. The primeraccording to claim 1, wherein the ignitable material includesalternating layers of reducing metal and metal oxide.
 12. The primeraccording to claim 11, wherein the ignitable material further hasinterface layers of reducing metal oxide between the reducing metallayers and metal oxide layers, the reducing metal oxide having athickness of less than 1 nm.
 13. A cup for a primer, the cup comprising:a tube having a side wall, the tube defining a first open end, a secondopen end, a tube interior, and a central axis, the second open enddefining a ledge projecting towards the central axis; a disk having afirst surface, a second surface, and an edge, the disk being dimensionedand configured to fit within the interior of the tube with the peripheryof the disk abutting the wall; and the ledge being dimensioned andconfigured to resist passage of the disk therethrough.
 14. The cupaccording to claim 13, wherein: the tube is generally cylindrical, thetube defining an internal diameter; and the disk is generally circular,the disk having a diameter that substantially matches the internaldiameter of the tube.
 15. The cup according to claim 14, wherein theledge extends around substantially the entire wall, the ledge definingthe second open end.
 16. The cup according to claim 15, wherein the edgeof the disk includes a first edge portion adjacent to the first surface,and a second edge portion adjacent to the second surface, the secondedge portion having a diameter corresponding to a diameter of the secondopen end, the disk defining a lip extending between the first edgeportion and the second edge portion, the first edge portion defining afirst thickness, the second edge portion defining a second thickness,the thickness of the second edge portion being substantially equal to athickness of the ledge of the tube, the lip of the disk having a widththat is substantially equal to the width of the ledge of the tube. 17.The cup according to claim 16, wherein the wall defines a plurality ofinwardly extending projections, each of the inwardly extendingprojections being disposed a distance above the ledge that issubstantially equal to the thickness of the first edge portion, wherebythe disk is retained between the ledge and the inwardly extendingprojections.
 18. The cup according to claim 13, wherein the wall definesa plurality of inwardly extending projections, each of the inwardlyextending projections being disposed a distance above the ledge that issubstantially equal to a thickness of a portion of the edge of the diskabutting the wall, whereby the disk is retained between the ledge andthe inwardly extending projections.
 19. The cup according to claim 13,wherein the ledge extends around substantially the entire wall, theledge defining the second open end.
 20. The cup according to claim 19,wherein the edge of the disk includes a first edge portion adjacent tothe first surface, and a second edge portion adjacent to the secondsurface, the second edge portion being dimensioned and configured tosubstantially fill the second open end, the disk defining a lipextending between the first edge portion and the second edge portion,the first edge portion defining a first thickness, the second edgeportion defining a second thickness, the thickness of the second edgeportion being substantially equal to a thickness of the ledge of thetube, the lip of the disk having a width that is substantially equal tothe width of the ledge of the tube.
 21. The primer according to claim20, wherein the wall defines a plurality of inwardly extendingprojections, each of the inwardly extending projections being disposed adistance above the ledge that is substantially equal to the thickness ofthe first edge portion, whereby the disk is retained between the ledgeand the inwardly extending projections.